3GPP networks are beginning to support devices and customers with very different characteristics, such as machine type devices, mobile virtual network operator (MVNO), data usage, etc. These classes of devices and customers may have different requirements from the Core Network (CN) in terms of optional feature support, traffic characteristic support, availability, congestion management, ratio of signaling to user plane traffic, etc. As we move forward the classes of devices/customers will continue to increase. One cost effective mechanism for operators to support these different classes of devices and customers is to create separate Dedicated Core Networks (DCNs) consisting of specialized core network elements that are designed and deployed to meet the requirements of these different devices and customers. It is cost-effective as the network availability or redundancy requirements may be easier to meet with different hardware and/or software than the existing core networks. Also, creating separate core networks enables independent scaling or specific feature provisioning for specific user or traffic types and isolating specific users and traffic from each other.
Typically, a Wireless Communication Device (WCD) communicates with a Core Network (CN)—e.g. one or more DCN—via a Radio Access Network (RAN). The CN—which may be a DCN—comprises a number of CN nodes. Examples of known CN nodes may be the Serving Gateway (SGW) and the Mobility Management Entity (MME) and the PDN Gateway (PGW) and the Policy and Charging Rules Function (PCRF) and the Home Subscriber Server (HSS) and the Serving GPRS Support Node (SGSN). However, this disclosure is not limited to a particular known CN or DCN comprising known CN nodes. On the contrary, the disclosure is also related to future CNs or DCNs comprising future CN nodes that are to be developed in the coming years. Indeed, the precise structure of a CN or DCN is not that important to the present disclosure. However, known CNs and known CN nodes and known Radio Access Networks are briefly discussed below to give some context to the present disclosure.
The Radio Access Network (RAN) covers a geographical area which is divided into cell areas, with each cell area being served by a base station, e.g. a Radio Base Station (RBS). In some radio access networks the base station is e.g. called “NodeB” or “B node” or enhanced NodeB (eNB). A cell is a geographical area where radio coverage is provided by the equipment of a radio base station at a base station site. Each cell is identified by an identity within the local radio area, which may be broadcasted in the cell. The base stations communicate via an air interface with radio terminals within range of the base stations.
In some versions of the RAN, several base stations are typically connected, e.g. by landlines or microwave links, to a Radio Network Controller (RNC) or a Base Station Controller (BSC) or similar. The radio network controller or similar supervises and coordinates various activities of the plural base stations connected thereto. The radio network controllers are typically connected to one or more core networks.
For example, the General Packet Radio Service (GPRS) is a wireless communication system, which evolved from the GSM. The GSM EDGE Radio Access Network (GERAN) is a radio access network for enabling radio terminals to communicate with one or more core networks.
For example, the Universal Mobile Telecommunications System (UMTS) is a third generation wireless communication system, which evolved from the Global System for Mobile Communications (GSM), and is intended to provide improved mobile communication services based on Wideband Code Division Multiple Access (WCDMA) access technology.
The wireless communication device (WCD) may e.g. be a mobile station (MS) or a user equipment (UE) or similar wireless device, e.g. such as mobile phones, or cellular phones, or laptops or tablet, phablet, machine type communication device or similar devices with wireless capability, and thus can be, for example, portable, pocket, hand-held, computer-comprised, or vehicle-mounted or other wireless devices which communicate voice and/or data with a radio access network. It should be emphasized that the WCD may be embedded (e.g. as a card or a circuit arrangement or similar) in and/or attached to various other devices, e.g. such as various laptop computers or tablets or similar or other mobile consumer electronics or similar, or vehicles or boats or air planes or other movable devices, e.g. intended for transport purposes. Indeed, the radio terminal may even be embedded in and/or attached to various stationary or semi-stationary devices, e.g. domestic appliances or similar, or consumer electronics such as printers or similar having a semi-stationary mobility character.
Typically the Core Network (CN), to which the WCD communicates via the RAN, comprises a number of core network nodes.
Examples of core network nodes are the Serving Gateway (SGW) and the Mobility Management Entity (MME) and the PDN Gateway (PGW) and the Policy and Charging Rules Function (PCRF) and the Home Subscriber Server (HSS) and the Serving GPRS Support Node (SGSN).
FIG. 1a shows a schematic overview of a well-known exemplifying wireless communication system. The system is a so called LTE based system. It should be pointed out that the terms “LTE” and “LTE based” system is here used to comprise both present and future LTE based systems, such as, for example, advanced LTE systems.
It should be appreciated that although FIG. 1a shows a wireless communication system in the form of a LTE based system, the example embodiments herein may also be utilized in connection with other wireless communication systems comprising nodes and functions that correspond to the nodes and functions of the system in FIG. 1.
In FIG. 1 the E-UTRAN corresponds to the RAN, which in this case comprises a number of radio access node in the form of eNodeBs (eNB) that interfaces with a WCD, which is denoted User Equipment (UE) in LTE. Several UEs are normally served by one eNB. However, for the sake of simplicity only one UE is illustrated in FIG. 1.
The Serving Gateway (SGW) routes and forwards user data packets, while also acting as the mobility anchor for the user plane during inter-eNB handovers and as the anchor for mobility between LTE and other 3GPP technologies (terminating S4 interface and relaying the traffic between 2G/3G systems and PDN GW). For idle state UEs, the SGW terminates the DL data path and triggers paging when DL data arrives for the UE. It manages and stores UE contexts, e.g. parameters of the IP bearer service, network internal routing information. It also performs replication of the user traffic in case of lawful interception.
The Mobility Management Entity (MME) is the key control-node for the LTE access-network. It is responsible for idle mode UE tracking and paging procedure including retransmissions. It is involved in the bearer activation/deactivation process and is also responsible for choosing the SGW for a UE at the initial attach and at time of intra-LTE handover involving Core Network (CN) node relocation. It is responsible for authenticating the user (by interacting with the HSS). The Non-Access Stratum (NAS) signaling terminates at the MME and it is also responsible for generation and allocation of temporary identities to UEs. It checks the authorization of the UE to camp on the service provider's Public Land Mobile Network (PLMN) and enforces UE roaming restrictions. The MME is the termination point in the network for ciphering/integrity protection for NAS signaling and handles the security key management. Lawful interception of signaling is also supported by the MME. The MME also provides the control plane function for mobility between LTE and 2G/3G access networks with the S3 interface terminating at the MME from the SGSN. The MME also terminates the S6a interface towards the home HSS for roaming UEs
The PDN Gateway (PGW) is a network gateway node that provides connectivity for the UE to one or more external Packet Data Networks (PDNs) 250 by being the point of exit and entry of traffic for the UE. A UE may have simultaneous connectivity with more than one PGW for accessing multiple PDNs. The PGW performs policy enforcement, packet filtering for each user, charging support, lawful Interception and packet screening. Another key role of the PGW is to act as the anchor for mobility between 3GPP and non-3GPP technologies such as WiMAX and 3GPP2 (CDMA 1× and EvDO).
The Policy and Charging Rules Function (PCRF) determines policy rules in real-time with respect to the radio terminals of the system. This may e.g. include aggregating information in real-time to and from the core network and operational support systems etc of the system so as to support the creation of rules and/or automatically making policy decisions for user radio terminals currently active in the system based on such rules or similar. The PCRF provides the PGW with such rules and/or policies or similar to be used by the PGW acting as a Policy and Charging Enforcement Function (PCEF).
The Home Subscriber Server (HSS) is a database that contains user-related and subscriber-related information. It also provides support functions in mobility management, call and session setup, user authentication and access authorization.
The nodes and units of the wireless communication system in FIG. 1 are connected by lines extending between the nodes and units. Each such line is marked with a label, which corresponds to the name used in the 3GPP specifications for the particular interface. This is well known to those skilled in the art and it needs no further explanation.
It should be appreciated that although FIG. 1 shows a wireless communications system in the form of an exemplifying LTE based system, the example embodiments herein may also be utilized in connection with other wireless communication systems comprising nodes and functions that correspond to the nodes and functions of the system in FIG. 1.